Field of the Disclosure
The present invention relates to a method for enhancing an interaction between graphene nanoparticles and a poly(styrene-co-methylmethacrylate) and to a blend composition obtained by the method.
Description of Related Art
During the past two decades, nanocomposites, especially carbon based nanomaterials, have become a novel class of material. When incorporated into a polymer matrix, nanocomposites have revealed remarkable improved properties, at very low loading content. In particular, graphene and its polymer composites have attracted applications in modern science and technology. “See Stankovich. S, Dikin. D. A, Dommett. G. H. B, Kohlhaas. K. M, Zimney. E. J, Stach. E. A, Nature. 2006, 442, 282-286; Si. Y, Samulski. T, Nano. Lett. 2008, 8, 1679-1682; and Geim. A. K, MacDonald. A. H, Phys. Today. 2007, 60(8), 35-41 (references), each incorporated herein by reference in their entirety.” Graphene is the “thinnest material” in the universe, and its unique properties make it more demanding in different technological fields, such as conducting films, sensors, super capacitors, nano electronics, batteries and bio-medical applications. “See Kim. K. S, Zhao. Y, Jang. H, Lee. S. Y, Kim J. M, Kim. K. S, Ahn. J. H, Kim. P, Choi. J. Y, Hong B. H, Nature. 2009, 457, 706-710; Robinson. J. T, Perkins. F. K, Snow. E. S, Wei. Z. Q, Sheehan. P. E, Nano. Lett. 2008, 8, 3137-3140; Stoller. M. D, Park. S. J, Zhu. Y. W, An. J. H, Ruoff. R. S, Nano. Lett. 2008, 8, 3498-3502; Eda. G, Fanchini. G, Chhowalla. M, Nat. Nano. technol. 2008, 3, 270-274; Yoo. E, Kim. J, Hosono. E, Zhou. H, Kudo. T, Honma. I, Nano. Lett. 2008, 8, 2277-2282; and Xu. Y, Bai. H, Lu. G, Li. C, Shi. G, J. Am. Chem. Soc. 2008, 130, 5856-5857 (references), each incorporated herein by reference in their entirety.”
Polystyrene (PS) and poly(methyl methacrylate) (PMMA) are widely used commodity plastics after polyolefin. They are applied in different fields such as bio materials, protective coatings, microelectronics, tissue engineering and solar technology. “See Burdick. J. A, Anseth. K. S, Biomaterials. 2002, 23, 4315-4323; George. P. A, Donose. B. C, Cooper-White. J. J, Biomaterials. 2009, 30, 2449-2456; L. F. Thompson, Willson. C. G, Tagawa. S, Polymers for Microelectronics. 1993, ACS; and Yoshihiko. K, Hirofumi. Y, Kunio. A, Langmuir. 2008, 24(2), 547-550 (references), each incorporated herein by reference in their entirety.” Incorporation of nanofillers such as carbon nanotubes and graphene into the polymer matrix can considerably enhance the physical and mechanical properties, which is desirable for different kinds of applications. “See Dresselhaus. M, Dresselhaus. G, Avouris. P, Topics in Applied Physics. 2001, 80, Springer, 448; Stankovich. S, Dikin. D. A, Dommett. G. H. B, Kohlhaas. K. M, Zimney. E. J, Stach. E. A, Nature. 2006, 442, 282-286; and Tapas. K, Bhadra. S, Yao. D, Kim. N. H, Bose. S, Lee. J. H, Progr. Polym. Sci. 2010, 35, 1350-1375 (references), each incorporated herein by reference in their entirety.”
Melt mixing is a technique used to prepare polymer nanocomposites. It is an easy, economical and efficient technique in which high temperature and strong shear forces are employed to obtain efficient mixing between the polymer matrix and nanofillers. During melt mixing, the polymer chains may degrade. “See Zhang. Z, Zhang. J, Chen. P, Zhang. B, He. J, Hu-G. H, Carbon. 2006, 44(4), 692-698 (reference), incorporated herein by reference in its entirety.” This can lead to better dispersion and covalent bond formation of nanofillers with the polymer matrix. “See Zheng. W, Shen. B, Zhai. W, Chen. C, Lu. D, Wang. J, Appl. Mater. Interfaces. 2011, 3, 3103-3109 (reference), incorporated herein by reference in its entirety.” To achieve full improvement in the properties of polymer/graphene composites, the most challenging step is to achieve a high level of molecular dispersion and interaction between graphene and the polymer matrix. Different approaches such as the use of peroxide during melt mixing, functionalization of nanoparticles and implication of low molecular weight polymer chains have been investigated. “See McIntosh. D, Khabashesku. V. N, Barrera. E. V, J. Phys. Chem. 2007, 111, 1592-1600; Lerf. A. H, Forster. H, Klinowski. M, J. Phys. Chem. B. 1998, 102, 4477-4482; Bourlinos. A, Gournis. B, Petridis. D, Szabo. D, Szeri. T, Dekany. A, Langmuir. 2003, 19, 6050-6055; Stankovich. S, Piner. R. D, Nguyen. S. T, Ruoff. R. S, Carbon. 2006, 44, 3342-3347; and Wu. G, Tang. Y, Weng. R, Polym Degrad Stab. 2010, 95, 1449-1455 (references), each incorporated herein by reference in their entirety.” However, scientists are still looking for more appropriate methods to attain better interaction between graphene and polymer matrix.
Irradiation is an accepted and useful technique to modify the properties of polymer blends. “See Spadaro. G, Valenza. A, Polym Degrad Stab, 2000, 67, 449-454 (reference), incorporated herein by reference in its entirety.” The irradiation process causes major reactions such as cross linking, chain scission (degradation), formation of oxygen based functionalities (oxidation) and grafting (in the presence of monomers). “See Gueven. O. International Atomic Energy Agency, Technical meeting, 2004 (reference), incorporated herein by reference in its entirety.” Similarly, when radiation is absorbed on the surface of graphene, defects form on graphene which results in a change of structure. “See Teweldebrhan. D, Balandin. A. A, App. Phys. Lett. 2009, 94, 013101 (reference), incorporated herein by reference in its entirety.” This free radical formation in polymer chains and disorder in graphene structure after irradiation may provide improved dispersion and hence a strong interfacial interaction between graphene and the polymer matrix. Compared to other radiation techniques, microwave radiation is an easy, cheap and green technique. “See Roberts. B. A, Strauss. C. R, Acc. Chem. Res. 2005, 38(8), 653-661 (reference), incorporated herein by reference in its entirety.” It has been used for synthesis of polymer composites, but so far no work has been done to investigate the improvement of interaction between graphene and copolymer composites using microwave radiation. “See Kristian. K. C, Becer. R. U, Schubert. S, Macromolecules. 2011, 44(15), 5825-5842 (reference), incorporated herein by reference in its entirety.”